Debt (Tables)

6 Months Ended

Jun. 30, 2017

Debt Disclosure [Abstract]

Schedule of Debt

DEBT BALANCE, NET OF UNAMORTIZED ISSUANCE COSTS (in millions)

	June 30, 2017			December 31, 2016
Total debt	$	3,829		$	4,109
Unamortized issuance costs	(50		)	(55		)
Current maturities	(1		)	(1		)
Debt, Net of Current Maturities and Unamortized Issuance Costs	$	3,778		$	4,053

Line of Credit Facility [Line Items]

Schedule of Line of Credit Facilities [Table Text Block]

AVAILABLE CAPACITY UNDER CREDIT FACILITIES (in millions)

	Total Capacity		Amount Borrowed as of June 30, 2017		Outstanding Letters of Credit		Available Capacity		Expiration
Andeavor Logistics Revolving Credit Facility (a)	$	600	$	50	$	—	$	550	January 29, 2021
Andeavor Logistics Dropdown Credit Facility	1,000		—		—		1,000		January 29, 2021
Total Credit Facilities (b)	$	1,600	$	50	$	—	$	1,550

(a) The weighted average interest rate for borrowings under our Revolving Credit Facility was 3.31% at June 30, 2017.

(b) We are allowed to request that the loan availability be increased up to an aggregate of $2.1 billion, subject to receiving increased commitments from the lenders.